SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c111a42f3d37be689c895efc9863fdd93f960ab4f9da0350b5f9caf45b46abf9' 
  AND token = 'MBVk3tBdJHTDeTQBVss3KUMhxXWP5RE2izMZ+jIompY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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