SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52dd9dd78f90c3c97b025b3b3bb6ee4a430163ab79429a61351ff9ffd6725d5e' 
  AND token = '/xJBNmjznCiJv/BbmjO3+P2yu39G9R8l4TvbrBjVL4c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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