SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aaa0c49e3a47a7de3fea651907f67dce711a304d2b19b4204add490a4466c760' 
  AND token = '7QeeBBFyq2cBIKqocmbprh37n43bKvzDCzvcGtsd+So=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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