SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '212dea206dd40cd66f17875d25414f3a953ad2baab626f781c93330db9d46a75' 
  AND token = 'AdNuFqXM+Fakl9FTPVYrNbvN8wyLsqBBLgWEpTAR0QY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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