SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a159997fe328c1864394fc82b10025a39440609da614b94168368ee3cb26fe6' 
  AND token = '6T0uOOAUz/YTI7CDNTXRLTSDSfcjLTC65SRTiIMauLw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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