SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '41d7e947b44716e4a8e50d78f1792f224d5cb3537689ec012378eb50f0035183' 
  AND token = 'zvCt/Lwwmb5TrwXUoNG4IrR+tumoPSCVHDSLMojWrAw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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