SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0b17731734803b870954f87d19fa9afe5b55f6ebfabf781c74515a8eaf03a480' 
  AND token = '2dgECMUztulJLi4HSTyZc/1ABP4+OiLR9sGyDxqZXjY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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