SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ec42ee3257846f4b544a0eaf9c28d0d5dc29a4a8dcd31319547862e1d21c8ff9' 
  AND token = '+KJtwiDUlC3P/jYuPwt9taFqsGocRVJdroIhS0ZxZM4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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