SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd639abd34f9c9e7dadac2a654840b5193323dd1213474f8ab802ca2d5919f735' 
  AND token = 'Q+KFmWF+8rXaXQtxVDkGf3JiZqvabvliec5xmALY83k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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