SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '788ed3ac3401bf247ea4b2aea75cff654bf1924cfa8eb76606ea4c2d31b69169' 
  AND token = '5SIP7Y0B82UozTQNTRFXMSznJPFN4Plk2RfioIfYoEk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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