SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '11639b631c95fa5cd9ccc5fcbae1139418f9cf708f4440cb35e35dc4cf1eb756' 
  AND token = '5verPez6AjP+xPDpGPPIHwN6CISEKONdScoRURx8hT0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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