SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aeec912be827998087cf40ded96ae10784465f53effd9e6ef5792b64e0d79267' 
  AND token = 'aBoOnEj0Sfz5TRRAKhXvgUUXJl3fx/QooOuwqpGMT5Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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