SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37a13939af858e8eb6c8b508b08fd7ed4158e66373af9a74b560f63b2afc4c84' 
  AND token = 'FaUZRjvyqunF/PPrvnvS5lw0B7udpHcw0TOg1QDsy/w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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