SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4920d775043a5125fc674c8f9bc7cf8943b26287d0c44e1f397d557e2a93e2b9' 
  AND token = 'lfWIXV6VvyY5z7fJvVLZ1n17cYCK/aVWiZf6uOBBE8E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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