SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '08c678f30dd467d66a6c0bb24a45b59d6c29301faa23b856f17071d8df57fb16' 
  AND token = '4LLnWAUC4KAxToBh6D+JYqvXFTnuyzeUvKHCOdoqgeE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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