SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d27fa02059996786306070dfc7bcbf94739091048f351a68a1e237b6306d84c' 
  AND token = 'l8m0tzevdNtqRQkoMZKJL9tAlgELJ+yG/yWJ6gXW8RQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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