SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6b3668446bd5cf7fe1acbccbc2ae4c05b0f98f8a9d08c53daa65aceb3beeace' 
  AND token = 'l4nAEdu7BFMJuQb1m6tgA3sD0d5VHRpVRIYmZcC08Lg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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