SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b5542f38d4c90b4a99f89acea97433222cbd0559da6b589a3514892ad1d43efa' 
  AND token = 'dGNdYx5zRhkS9OGS78NwTmIWbjt4q8OXArFZ+8gG58U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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