SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7a314c38890201a13ac8e2ceac0b7a6f96a043e8d78d7f735418e5b0d5c7f71' 
  AND token = 'cKLs63gxlcUE1tHMBQlb5ngXtNQWBiALXzvEnf5CN7U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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