SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b096a17a2901f3b8cb1c9d530dda5ef3bf6a576cd0a9ef91aa611fe743e93d74' 
  AND token = 'NmKd5ddNb214TaEc3LUa48wr3Mh4Dt1jNo1Ai0JEftQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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