Sandbox

SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '4cbb1345abe3ce279ab8d0b92df0bd9085b1e2a1deb37563925a8b5ce64d6d21' 
  AND token = 'vhrd+8NspDFnzQlFQVtzHAoI9XOAwwiGcq90yQG9ous=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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