SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b6e5eac188883c8e3fc058c5bde0c74ada47f33b02470872a72fd9c1634bb07' 
  AND token = 'fd5vzJk00MGZRds2ea+hvO03RFKvi8kQCTmtvKFe1Pw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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