SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3e87e05bd4d98342872572620857fec69c07230370bd4da6be048ba09a0e7ca' 
  AND token = 'YpmjnuPsaF1nFpYN+jWCRTLEV9PsBToQHmQDxwS7uEc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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