SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8652a1d5a7b3f784065517f67c2d3787ad4fc62324552ebe74b9aa7165cfb2b' 
  AND token = 'Sl/TsHPP1dQg5ZYw9tWMDFtgEkMlsY5nbSLjroOjV1I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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