SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eeb3c31b739573dd62350f6ce0f472fb18535f800575eb3918e1d891abf8965d' 
  AND token = 'HJukCtaAvUT3RCG6GjfThCcXpULceEgugvjQ9CWUdGo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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