SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d2cc638d77eca021ea6aa251d5f11377f4b5e9af987172180bff3cdd0e632c9' 
  AND token = 'Lz/KUOx1+mwM2C9FAdZnlEEaGcCHON7id2ABTVh3jhI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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