SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26d3219e55b8951a0fada9436942a1c6f48c2d2f0eea9f6e2032587504444804' 
  AND token = 'w46mBSJ0jPiqRKYJXg2OPAeFIAQ1lpQDB+x+n2jp/fQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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