SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '614df816fdd8fa85bd6596ca00b57d202d2dc78331bf559b205707fa342785fb' 
  AND token = '5S+zaCpVUJApJD9k4PNzxX+Xg3gZOiBGSPzSB+XSGts=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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