SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da64cebcddce5de5daa3c69958c5319353affe46636054d85bd3db97915ac28d' 
  AND token = 'vrwNWU77D0swL37cSwUzsqduKfFJip8zR9tAglLnPZ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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