SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '431231d9307cea1f3228c8bd46a9bf9d1f7356986c8865e2589452da9b774b93' 
  AND token = 'fvLW8D8F+HovImkpj0fLaWlJPZvBHZ7PUOG7VqXZQzo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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