SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3620a87bad4f6c37d498853454b2fad38ae6b481849f6d1f81cbb1a77e674f8b' 
  AND token = 'paTCYOsCGPfZcAmLl5CgLtILxAzUFoIpuwxxdh6xvNw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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