SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '17f64434178ba9ccb1586c13b4c4a431c6f0659354cab17d53b1624b79bcce15' 
  AND token = 'UKWih7rgT0aWKb2pBiahrd2GbIxHbBItdBSi0rsf6b0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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