SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c315591dea6d42eed435fc20449e2e62f66bfeeb60b1038460630f757d12d165' 
  AND token = 'vx8kSlro6bx4FIRfthYqV1EnXueT3PJLiJ7UIQGP28M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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