SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'faf34904bf5a7d1b79fa091fefa826aff9555df3b96737fcc3b1ede0c3d3db47' 
  AND token = 'epjxooSyxV+x3G6v40ZR+mJhFCcKWY/0PeXq7FeQ+Zg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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