SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6d443702c3e44731995f7a51cf564d4b8af0bc6367ec23922a55915b13bf3c5' 
  AND token = 'av1iiJXulBSiCrmsWJiFf6mi01JUt5InleDXVnfyLZI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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