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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7a6ccdb2e5b21ecfc1bf20f6a0cf7e0eb5c7429f5a859b0ddde6eb442d6fec5' 
  AND token = 'fPx6657LAD7upeo7xXE+BVcHce6fT58KKGW4QX/gv4E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}