SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68bbc5502151c669750913d60cb53576d64b4e7a109d26ce9a5c739a4ed7cdea' 
  AND token = 'fzrkQqXUb9Mx0EXTanWiBD/qjz1X5zOfMkp1TSlgzsw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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