SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ace57f929668145004d1ae1c66c49c90bfab8ebe539a8b50a98aef014480f40f' 
  AND token = '+x3x/Eoc3WOEIR3UeOdfyegmQECJQGu8U2ybC/z3LSU=' 
  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"
    }
  }
}