SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4ffb866203b5210036bd72344cfb4721995f7e818e869a8f88f8c0dfff2540c' 
  AND token = 'fJSiITPuRLoBinOz0o5ScY79hrqjJhgkVbCQZOFQ59E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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