SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '976445774987abec7a52235d7991319889d7a9f2a0ce909906ec661a90040dd4' 
  AND token = 'rRhHGCvMdKbgLl3XuGb8+7iB+qhvnwje0/VXHw2vu2s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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