SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74772f967fb2e23e5f65fcd937a13d89a6cc44f3c9d2f5b00735b14858eb5aaa' 
  AND token = 'VPlcnWARAjRgscaCKhCqG7SV0DczTZKhxr38NsB0MT4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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