SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d6cc94c5d9a0ba6a7c1716c51de2e15df7fe769e7c1564eb4cf59fb6afa3a49' 
  AND token = 'HZrcZ3RZDuEEGLIDaMjqvvIJ4+7frAWEeXV0+H+Q63I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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