SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b287b2f7509c4fabe9a7be5e2159a8d5b2c138a9c8d416a97819d249b2d7eb05' 
  AND token = 'WCwIjbwOTdFNtL7l5vVZR664KOxh1561NfsxTGkiPls=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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