SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9897cbdcd323c8037da8fb0e739d000a42d833ecfe99390a9afb1cc4c6457acd' 
  AND token = 'aNaxF+6PacXfbuAh7cMl4w1Snr9GJoyKbUlcC/u4laU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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