SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '03ff88653b31d3682fe5fd780c55be9dfc9e7d426718d3efab41f119a384572c' 
  AND token = 'AS9kg+QnmEWkPyJ3qlHRCJ5jrgsop3FwFoxjBH9iruE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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