SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '10710eeefad974f82c6589d04d9122449d3aaf76828068be93b0a6cb0be85cf4' 
  AND token = 'UPBeqBADwSaIDnfSMF2sDc2ZXJeO5wH7/Iz92bCVNek=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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