SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '0f1dcbde55d7182e61768845ca9adca7348f636b83200d3c639b5ca3a4899d08' 
  AND token = 'mxCF2hY8EUSUvi5G2Hs6F/kzLrgjAy+1u/xbywKwDIM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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