SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c882c719c04e4feccb9aebed271f43430183a510f57879aa0297e7d1415a8f2' 
  AND token = 'wyvYjDVXI1zhUX0jYxwC18vjzwMXIG4GOsTvuiBe0ts=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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