SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a824d17fcb1f2c8b7ac43fe2670979b54e8ee4ca478bee3955aff8ad32baa64d' 
  AND token = 'tTKNvAyIfDHJ9dMIPdWy/Ni5CYkvLGJp0AaxfJ5ba0o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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