SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35a86e4cc7039b15aef4948f3d145a878817d5045a2e526454b223bf6843463d' 
  AND token = 'CZe889U5BtBVw3wnQdvzLvjOshPoJn9iARaNRaTKnys=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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