SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b74a3f477fe69dfe615cd7edd376299625059810b31d7f11e2c4cd247ef67617' 
  AND token = 'wLdp+BbSv9IjpLoxLlXRKdUoZkOCK/GnVYgJD+nORRc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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