SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7cca34d133618348d624ed7fb37b8520494265636d33f6acc5ab1c49c416744' 
  AND token = 'knBB35ehvydcOh3lXHlZRyfnfhnYo7WcV6+1PVO7rR8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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