SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c298b3a974816f199d0f04d26bfad412e8511a226c30dd83557c4422f1825b61' 
  AND token = 'x/FfDRUP5G55wNfVeVxvfZ6UKB28hnI7t6MqeKDLeg0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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