SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29d14d3bab16dd2ba21d5bf87e808661fa0c5394185fb016da97084c02970738' 
  AND token = 'WtsOC72upGCq+BmJnk9ji7CXhkAOXLiHRJ6y1Cj+5YY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00008

JSON explain

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