SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '599a77c21c1dc353e1760e6da18c2674a93a40de2f30ab65f730cf96729c8ecf' 
  AND token = 'GY5MxKDRd8arARrbBEzRmOhPwXrO+b84qDjHLuL9HGg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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