SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18fa4d678f3088e71216575307bad2afbf20a2bcaa3f2426518e80d25e673df0' 
  AND token = 'sScecRJGtwPdQzPJcIt9fV/y8PmVmUDb5l3B/xpdO4U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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