SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd1ed4774a38d5c93a8b2527f5b9ee553f8cf2b260a2894945e8b04f5dcdb1bb9' 
  AND token = 'aWgHlMkBmNvn1kpICzU/rHFCoxsaK+oQVl2vXlpJPOc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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