SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a742b42f9b5b91aba9ca4c41ebd0c05f093204ad158388af87c47221e9e13a31' 
  AND token = 'qKxxVSbkPo7xS/uChqpjvIL4GaKkwjBHczWsopb5Jsg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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