SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86bb470a91d3e9ee38aefdbb78792b4ee932a726073084cf397ae489e56a29af' 
  AND token = '2NNY9idj9PZE0BA6UjKR18R2HQgOuacQVaktBJopcD0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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