SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a57eed629dc42bda0f1304f64dd93719be4950810c1043713e0ff6178f78ae7b' 
  AND token = 'JhbJK33Lwjvn0Mx0/+BRSABvVO0Edxv5FzA/Omsjc7M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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