SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b43dceadc88797e1ea743fa93cbd67e79126ecb1f3c68390677bde0fa4a7346' 
  AND token = '8HmJznYjF7HTynQ643fanVq0vQXSHjK/T5uE0NBnZGM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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