SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc4750c63fa7d891bcae7317028d60e5d3c3293156f12acd5c9ad71353f054d3' 
  AND token = '/jPJdqjoCJWy4k20BF6WSUb6UDVA2El6UKQMwa5lGTc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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