SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ff29ba102f687de4b17a174527fd0c08f0c41333a97512e07010390afd448ee7' 
  AND token = '8v+PiNGCSt0YrtOB++4aplXMHQGR98en7L5ULIuW+QU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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