SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '114a76b181226aaf309fa7a2775bc326a3549f68cdec10d71590c8fb90f78088' 
  AND token = 'hBkFpo0wCNZx0S+YdiUiRZJ66BBgRBYqHtvetfTrxsQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00057

JSON explain

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