SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aaa58d0cf99959f94162842ce83204876e0f8d381796ce11c21ba9930e574cd3' 
  AND token = '+OKExu5pzXVWyWUjwtHL2IYhW1wElrKZjfomkRUqPMU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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