SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16d471ce537c70088aac303aa3a0cd994b9aa456dd0e84f1a7ead8d5aca2ed46' 
  AND token = 'CNRtLGS/aCdEB1U6peo/KqoXDlQhOAcwwpiRs51Ussw=' 
  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"
    }
  }
}