SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40f1845a1940ec22bb3912d60d0937dfa80e9241bdc4c4706e2027f279c75014' 
  AND token = 'lbqOSPMrN7gqxCJrR1Ltjj1ZJQvwUsKqLIFWtahR08E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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