SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b433c1780576abda4e7553653f7c0960736d5581370ae7163961bef51de1f6f2' 
  AND token = 'tO6XLronqXz79GVlkOyfeorfmvAOzGE93h34982UjHM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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