SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '97fc6d3842ea0a4159659991bd7523d8bc548611a980240d8dadfb22639a0f30' 
  AND token = 'JYng3/CrRF08+wymFWDHuWkgOFyIQ7Yz+8+xvdXhSdU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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