SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea36db3bcf5fccc5185d2ac26056745a17f00dc13c1897459fafe9c4a354534b' 
  AND token = 'B0+CQj3qwI2l4jzXZ9uyyMpPP7r/BJv+hvDvI/Ot+XY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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