SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0826b125cfdeb5e09de3300f689090fb44d7bc4fbc4b0beff06398afc1f77326' 
  AND token = '8Cr4uTQQHdyQPWJqLapNYMMZ6FrI8NT6EjJWEPrhXMQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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