SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '560a479243a1f0676f4a90fb911b348a930ad236dc94ba0ca30a51ea3e18ace9' 
  AND token = 'LzmhtDvvvJR9ftLWBJDW3rUVsV7uJqzoKm/Qy9BtdYM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

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