SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf91c2e9427668438957081617c86ef2f60c01f1d679d3573b3614b7676bd677' 
  AND token = 'NSupkaYCT/lVcjbOSZo61TmpVaOz2e44nAjLSLfsKS8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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