SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96696e6fd4520078aa65cfc3177f481ddab897efc4094af65680d91d258e4ed5' 
  AND token = '2fcK2JALWeZHaJ3TzLuXENLfXGKY3N1PSj5LzpZKv/g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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