SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0ff47c0fca9b0b4a24663e77286c8db7354ff7ebee55b28145e8d977345fc21' 
  AND token = 'vwc6m8uGU76EKugaKVQ+/epicF2z7DIFs91UQuX48Oc=' 
  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"
    }
  }
}