SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '319a1de43e35cb6a16b8af896493503b66d0d543fb50a937a2d6bb4edc1d0f6d' 
  AND token = 'zJUZGKAPujVLN2GxvVRP9lwqEFKeDOQVHnmVJJpZSNU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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