SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '559dbd64d6608ede5eb230d662107acba3ae3c7b2e2cf7e1c20642b9d5207f54' 
  AND token = '5pIanX4p9kWFZNnnLUrViOrVT/R8dqOarJljtaXTNHo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}