SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e62b3ee30edd536d07fbbd6a8ea2c21598a8b8e932146339570cbd484457864' 
  AND token = 'eZdBMn5IWe0gvIq82rxoyEcZEWx88kNKpgBXLMmBJVc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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