SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bae6e0f851b198716507fbd176d750ecc1120c84f5c0757470239922cafa8084' 
  AND token = 'OMv43M9R44XT16/zZn9xG4R3lxPRmM4UssZtxGxcShY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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