SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '883bb148b02009823a6aace9013b98c21477931bcb14cd6eccd03ffc9eca1858' 
  AND token = 'gaKbsrJlzVIY4Jtwk1A7ZxiA/tgYCtisZPFAXr9ZSjk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}