SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '18fe281fdeada77bc442bd50c63710e80676b90e96ef5a24f8109e05b03cafe7' 
  AND token = 'vUAJ0GJDn7hO5hCXkt/JyAp8d94YvPu4nDwCNBRYtwM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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