SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37280bddf31da74cd28d508b8cf37542f65d67ca7f4b13d5f4408cb847c0fa07' 
  AND token = 'ntHtQwDhpXpCsWw+Ocih9gA58Swjitkm+spFyAiHiSo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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