SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c2218a04d7987e55d263c562a19e9dca668bfcaea77ffd4ef889ce21cd58b61' 
  AND token = 'AiehyW7JLdN9kz+Xsw02MkISjmgyhHdxk/zcBknsiV0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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