SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '534fa228c4103caafcf242a21c6bd7627177065716943a3336dfc282f14b0dbe' 
  AND token = 'xh+94DcDB8cky0FvoR2pkNNop6oPNM9EDgODv+bqhhw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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