SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99f6598d7af7273b2fa40e4fd7db19f47f9d4bd19232544daa56f78ab58a7037' 
  AND token = 'qmyOTwozIG/g2zBAHLxTXKvvGqdKjvn34ABqgYf0sa0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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