SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57292cbd5c6c7e320dff8de2aca2ca163a57475348af298c207331f847a8a893' 
  AND token = 'WBQORjQmbM1T5pGVw7YJgT5U+2w2oZFUi42kAcpcBFI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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