SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '915614ee2ba316d4352783918d12dec3ab5f91127c0c34ff01318556f96bcd34' 
  AND token = 'lBxualWuxF94UvLW1wEEnrKtbPGXDhRISjuhW62eKek=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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