SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '7ce9735096278a485e80d31abab03f3fde2fc1e36038c72574c6e23e7044068f' 
  AND token = 'db1dFGTS6spH2jmCJtfRMKyhVd4XLiYTyj9d/gelQBw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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