SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e22c9d4641652d18fd3ad1ddcf0d6836f5a05a5307a650e4b44b04b88b29b76' 
  AND token = 'ppStApDBvMET0luzbMpx1dZKK13FgYv57XFF0HgwKbI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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