SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f14d10f04741b4cf653909e69ac76849822e2a7aaceb407e56b528cf6694f05' 
  AND token = 'W3MibZ0AqjjNZIoDapP7d5tkPnKdZGz2scQu5oiEdm0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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