SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ed6ffaee9a2a32dabf2d207da8625d6f4eaff114f9b45369991ae0794383a1b3' 
  AND token = 'QgkdfdeXWEcqcFZgk6TaSZMeWVclblfqIP+c1rUdGqI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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