SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4539e6da1293d8b35173c293e509d764f127fc147162f57b5eab5ffe82360f32' 
  AND token = 'VTBYB2zzTCv3ORJXY5IQEEYDmhVuyq4kZo6IHGPVpD8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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