SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a14191ec4959d4a6d547eedc12cb87cb122c6e6a6a26a817da4b1dde26c3ac5' 
  AND token = 'nUDmngDNKS907+Gq4N5whZhcYynTeNMa8AQNfcFhXho=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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