SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '18c16fcc39168876033aaebce20766610200cbfbbbdf99d64076a2ef55e09bd8' 
  AND token = '6Jb2W/Gn9LqQ8lwc4mnWe79qCP+NFRUPBuof6xqjzdY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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