SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9679d8404837a4a5f3ab2f978d88dc03dcf4271cf2a0a4d390caa0df41278276' 
  AND token = 'p/FJst1ciUBZQlvpouzcsXj29lRApsUDsG5165uu5aY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}