SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5dd0d475a2bb2b8bf4eac81399e46f074a4a4442f9c514a28e7d2436244a51d9' 
  AND token = 'g0TY9vCBBGTVJVst1jyAKnAV3q3VQ6M7MTchxfck+QU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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