SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3ecb951284e5196afe0d72b509f37af6c4af8eede4b3837c6870f8255aa6bf1' 
  AND token = 'uEidjKEX3wGlbSxOiZTZ+e8c1oRLeaTMY0incA9Sglw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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