SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5498607e9b4c8e0d19727992993df149bdeac9b8411e90306024b42bb6a45175' 
  AND token = 'zlAvGNauwI1Fct5gXVXW+/ZVinxv4XIjeocQ2pQIh/s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00073

JSON explain

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