SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9921c091afccac195346086c88b468d0a5129492650c411b2d37419791240e71' 
  AND token = 'Jw/bUrLhXG4lg6i+FIGRCqqZmCikkFJJ73BtTxaH5Vc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}