SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f86c6e1fbdee3c5cb85c1beaae617378e9c065d5fce01660da3c3fa04c59d64e' 
  AND token = '4DJVYobDISQiB5tGi920nPufDOGNeMnxIfsTQZUzfug=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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