SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb4b51893a4c0345fe09fd627198b7002dd81316d5b72f35e57c87565fd5efd8' 
  AND token = 'wCUO2/rjKhwrDKvcOJgKOilX8pPdsZGx/OBbhid6CBw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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