SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '824b6fcf83cd01736322b81d9819fbdd229933aca0ab09d9e9034f20c4df6505' 
  AND token = 'syv+VzrrYSHg/6wFNpyVD6TYnPzFy12WqufUHoYPG/4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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