SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '441c3b0e604c20d4244d8347e6003796ea46f72e530f1de14c7c76a39eee156d' 
  AND token = 'R+paHvioOTsw6phaCmvCA9ANQzVOxnnJvCDtd95sVws=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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