SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '893d79651a918de9f6d024ce8f93387f65cd2a83d9578432cf93df61f85a01ae' 
  AND token = 'vNFlXKrOujm1/uZJ0t5Q4hszXqiWmUYmKtGbe+B7dv4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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