SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f25ac93002ad623b91cd8451e539b5d6042cb65fbcc72affcd8385b34894fd7' 
  AND token = 'Nxf7RZdevGD+tEappn9SYGLv+BY9GZUDZ004zW19uIg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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