SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7649ce6d8e71a2b0ad625e1addbd249bbfdf3ae767ad047f24f52c2520f43499' 
  AND token = 'hnrhC1aR9nXkwi6vOMHTWAxmPqHg7jgdjoIF6gh58Ko=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00061

JSON explain

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